Abstract: For metal matrix composite materials, adding alloying elements is an effective way to improve its comprehensive performance. In the present study, the carbon nanotubes (CNTs) reinforced aluminum matrix (CNTs/Al-Si) composite foams with Si element were prepared by high-energy-ball milling and space holder method. Quasi-static compression test was carried out to study the compression properties and energy absorption performance of CNTs/Al-Si composite foams. The effects of sintering temperature and Si content on the microstructure, compression and energy absorption properties of the CNTs/Al-Si composite foams were further studied. The fracture failure mechanism was analyzed by the compression fracture morphology. The results show that the density and bonding of the CNTs/Al-Si composite foams increase with the increment of sintering temperature. When the sintering temperature is 600℃, mass fraction of Si is 7wt%, the yield strength, plateau stress, and energy absorption performance of CNTs/Al-Si composite foams are 98.4%, 167.7%, and 166.4% higher than that of the sintering temperature of 550℃, respectively. Moreover, the addition of Si element can refine composite powders during ball milling. Both of the strength and plasticity for the CNTs/Al-Si composite foams are improved after alloying. Compared with CNTs/Al composite foams, the yield strength and plateau stress of the CNTs/Al-Si composite foams with Si mass fraction of 7wt% increase by 58.5% and 117.8%, respectively. Meanwhile the energy absorption performance is significantly improved.